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| United States Patent |
5,705,529
|
|
Matyus
, et al.
|
January 6, 1998
|
N-benzoyl amino acid derivatives pharmaceutical compositions containing
them and process for preparing same
Abstract
The invention relates to novel N-benzoylamino acid derivatives of the
general formula (I),
##STR1##
wherein R.sup.1 and R.sup.2, which are the same or different, stand for a
hydroxyl group optionally bearing an acetyl group; or a C.sub.1-6 alkoxy
group optionally substituted by a phenyl group;
n means an integer from 2 to 15
as well as their tautomers, racemates and optically active individual
(pure) isomers or mixtures thereof and the salts of these compounds and
pharmaceutical compositions containing these compounds.
The invention relates also to a process for the preparation of compounds of
the general formula (I).
The compounds of general formula (I) inhibit the peroxidation of lipids and
therefore, they are expected to be useful for the treatment of diseases
being in an indirect or direct connection with pathological oxidation
processes, chiefly for the treatment and/or prevention of ischaemic and
reperfusion tissue injuries, inflammatory reactions, atherosclerosis,
various degenerative neurological disorders as well as for delaying the
natural process of the ageing of cells.
| Inventors:
|
Matyus; Peter (Budapest, HU);
Zara; Erzsebet (Budapest, HU);
Farkas; Lajos (Budapest, HU);
Papp; Agnes (Budapest, HU);
Simay; Antal (Budapest, HU);
Toldy; Lajos (Budapest, HU);
Andrasi; Ferenc (Budapest, HU);
Goldschmidt; Katalin (Budapest, HU);
Hodula; Eszter (Budapest, HU);
Mathe; Ildiko (Budapest, HU);
Sutka; Klara (Budapest, HU);
Fittler; Zsuzsanna (Budapest, HU);
Vitkoczi; Valeria (Budapest, HU);
Sebestyen; Laszlo (Budapest, HU);
Sziraki; Istvan (Budapest, HU);
Rusz; Marta (Budapest, HU);
Gal; Eva (Budapest, HU)
|
| Assignee:
|
Gyogyszerkutato Intezet KFT (Budapest, HK)
|
| Appl. No.:
|
540924 |
| Filed:
|
October 11, 1995 |
Foreign Application Priority Data
| Current U.S. Class: |
514/541; 514/616; 514/617; 560/41; 562/508; 564/155 |
| Intern'l Class: |
A61K 031/215; C07C 229/14 |
| Field of Search: |
514/541,616,617
564/155
560/41
562/508
|
References Cited
U.S. Patent Documents
| 4515920 | May., 1985 | Erickson | 525/54.
|
| 4904680 | Feb., 1990 | Matsui et al. | 564/155.
|
| Foreign Patent Documents |
| 0011845 | Jun., 1980 | EP.
| |
| 0051828 | May., 1982 | EP.
| |
| 59108 | Sep., 1982 | EP.
| |
| 173441 | Mar., 1986 | EP.
| |
| 0393355 | Jan., 1960 | SE | 564/155.
|
| 858426 | Jan., 1961 | GB.
| |
Other References
Journal of Org. Chem., 46, pp. 4524-4529 (1981) Bergeron, R.J. et al,
"Flexible Synthesis of Polyamine Catecholamides".
|
Primary Examiner: Gupta; Yogendra N.
Attorney, Agent or Firm: Meller; Michael N.
Parent Case Text
This application is a continuation of application Ser. No. 08/085,003,
filed Jun. 29, 1993.
Claims
We claim:
1. An N-Benzoylamino acid compound of the formula (I),
##STR12##
or a pharmaceutically acceptable salt thereof wherein
R.sup.3 is selected from the group consisting of a hydroxyl group and a
C.sub.1 -C.sub.10 alkoxy group; and
n is an integer from 10 to 15.
2. A pharmaceutical composition for the treatment of patients suffering
from disorders being in an indirect or direct connection with pathological
oxidation process occuring in an organism, which comprises a
therapeutically effective amount of a compound as defined in claim 1, or a
pharmaceutically acceptable salt thereof, in a pharmaceutically acceptable
carrier.
3. A pharmaceutical composition according to claim 2 wherein the disorders
are ischaemic and reperfusion injuries, inflammations, atherosclerosis, or
degenerative neurological disorders.
Description
This invention relates to novel N-benzoylamino acid derivatives of the
general formula /I/,
##STR2##
wherein R.sup.1 and R.sup.2, which are the same or different, stand for a
hydroxyl group optionally bearing an acetyl group; or a C.sub.1-6 alkoxy
group optionally substituted by a phenyl group;
R.sup.3 represents: hydroxyl group; C.sub.1-10 alkoxy group; or a C.sub.1-4
alkoxy group optionally substituted by a phenoxy group optionally bearing
a nitrogen-containing substituent; or an --NR.sup.4 R.sup.5 group, where
R.sup.4 and R.sup.5, which are the same or different, mean: hydrogen;
hydroxyl group; C.sub.1-12 alkyl group; C.sub.1-4 alkyl group optionally
substituted by a hydroxyl group or an amino group; or
R.sup.4 and R.sup.5 together with the adjacent nitrogen form an optionally
substituted 5- or 6-membered heterocyclic group optionally containing an
additional nitrogen atom, this heterocyclic group optionally being
substituted by an oxo group or an optionally phenyl-substituted C.sub.1-4
alkyl group or C.sub.3-5 alkenyl group; and when being piperazine, this
heterocyclic group may be substituted also by a diaminopyrimidinyl or
di(pyrrolidino)-pyrimidinyl group; and
n means an integer from 2 to 15
with the proviso that:
when R.sup.3 means hydroxyl group and n is 5, as well as one of R.sup.1 and
R.sup.2 means a 4-hydroxyl group, then the other one of R.sup.1 and
R.sup.2 is different from a 3-hydroxyl or 3-methoxy group; and
when n is 2 or 3, then R.sup.1 and R.sup.2 cannot simultaneously stand for
2- and 3-methoxy group,
as well as their tautomers, racemates and optically active individual
(pure) isomers or mixtures thereof, the salts ot these compounds and
pharmaceutical preparations containing these compounds.
As an other aspect of the invention, a process is provided for the
preparation of the new compounds of general formula (I).
The novel amino acid derivatives of general formula (I) according to the
invention significantly inhibit the peroxidation of lipids and as a
consequence, exert a number of valuable biological effects.
In a particularly preferred group of the compounds of general formula (I)
each of R.sup.1, R.sup.2 and R.sup.3 is hydroxyl group and n is 3, 4, 5 or
11.
In an other preferable group of the compounds of general formula (I) both
R.sup.1 and R.sup.2 stand for hydroxyl group, R.sup.3 means a C.sub.1-10
alkoxy group and n is 10 or 11.
A further advantageous group of the compounds of general formula (I)
consists of substances, wherein both R.sup.1 and R.sup.2 mean hydroxyl and
R.sup.3 stands for a C.sub.6-10 alkylamino group or a piperazinyl group
substituted by a 3-phenylpropyl or di(pyrrolidino)pyrimidinyl group.
The compounds of general formula (I) of the invention represent a substance
class only less studied up to the present.
A few publications concerning this type of compounds are only found in the
literature. Thus, A Bottazi et al. ›Riv. Farm. Ter. 11, 215 (1971)!
described the synthesis of 6-(3,4,5-trimethoxybenzoyl)aminohexanoic acid
and analogues thereof containing carbon chains of various length. G.
Razzaboni et al. ›ibidem, 11, 221 (1971)! published the effect of these
compounds against the heart-damaging effect of vasopressin. In these
papers, 6-(4-hydroxy-3-methoxybenzoyl)aminohexanoic acid was also
described but proved to be inactive in the test mentioned.
›(Dihydroxybenzoyl)aminomethyl!cyclohexanecarboxylic acids and
6-(dihydroxybenzoyl)aminocaproic acids inhibiting the platelet aggregation
and migration of polynuclear leukocytes were described in the European
patent specification No. 59, 108. Out of the
(dihydroxybenzoyl)aminocaproic acids, 6-(3,4-dihydroxybenzoyl)aminocaproic
acid has only been characterized without any data about its biological
activity.
4-(2,3-Dimethoxybenzoyl)aminobutanoic acid was used as intermediate in the
synthesis of polyamine-catecholamides ›R. J. Bergeron et al.: J. Org.
Chem. 46, 4524 (1981)!.
Benzamides substituted by one, two or three hydroxyl group(s), were
described in the published European patent application No. 0,353,753 to
inhibit the glutamate receptor. Mono and dihydroxybenzamides with a
related structure were published by S. A. Minasyan et al. ›Arm. Khim. Zh.
39, 169 (1986)!.
It is known that, due to their adverse (harmful) effects damaging the
various organs of vital importance, free radicals contribute
pathomechanism (pathogenesis) of many diseases, such as disorders
accompanied with ischaemic reperfusion tissue injuries, degenerative
neurological diseases, inflammatory processes or atherosclerosis ›see e.g.
C. Cross et al.: Ann. Intern. Med. 107, 526 (1987)!.
It has been shown that primarily the phospholipids of the cellular membrane
are damaged since changes accompanied by partial or total loss of function
are induced in the membrane by the reactive lipid radicals formed by a
radical initiator in the presence of metal ions.
Thus, recently a continuously increasing therapeutic demand has appeared
for active agents capable to protect against the harmful (adverse) effects
of free radicals. From this point of view compounds inhibiting the chain
reaction of the lipid peroxidation process by trapping of the radicals
and/or metal complex formation may be particularly valuable.
The best known natural antioxidant is vitamin E. Recently, a number of
compounds with closely related structure have been published ›see e.g. D.
A. Janero et al.: Biochem. Pharm. 40, 551 (1990)!. Although these
substances strongly inhibit the lipid peroxidation in vitro, their
therapeutical use raised several problems: e.g. usually high doses of
these compounds are effective under in vivo conditions and their acute use
is limited.
Lipid peroxidation is strongly inhibited by a novel-type steroid
derivative, the compound U74006F ›J. M. Braughler et al.: J. Biol. Chem.
262, 10438 (1987)!. Although the in vivo activity of this substance has
also been proven, its expected therapeutic use (mainly in the treatment of
acute brain injuries) is a priori significantly limited by its weak
absorption and relivatively rapid metabolism.
It has surprisingly been found during our investigations that the novel
N-benzoylamino acid derivatives of general formula (I) of the invention
inhibit the lipid peroxidation and, due to their favourable biological
effects, they can advantageously be utilized in the indications mentioned
above.
According to the invention the compounds of general formula (I) are
prepared by:
a) reacting a benzoic acid of general formula (II),
##STR3##
wherein R.sup.1 and R.sup.2 are as defined above, or a derivative thereof
suitable for acylating
with a compound of the general formula (III)
##STR4##
wherein R.sup.3 means hydroxyl group, C.sub.1-10 alkoxy group or a
C.sub.1-4 alkoxy group optionally substituted by a phenoxy group
optionally bearing a nitrogen-containing substituent, and n is as defined
above, to obtain compounds of the general formula (I), wherein R.sup.3
means hydroxyl group, C.sub.1-10 alkoxy group or a C.sub.1-4 alkoxy group
optionally substituted by a phenoxy group optionally bearing a
nitrogen-containing substituent and R.sup.1, R.sup.2 and n are as defined
above; or
b) reacting a compound of general formula (I) prepared according to the
process a) above, wherein R.sup.3 means hydroxyl group, and R.sup.1,
R.sup.2 and n are as defined above, or a derivative thereof suitable for
acylating, with a compound of the general formula R.sup.3 H, wherein
R.sup.3 means C.sub.1-10 alkoxy group or a C.sub.1-4 alkoxy group
optionally substituted by a phenoxy group optionally bearing a
nitrogen-containing substitutent,
to obtain compounds of the general formula (I), wherein R.sup.3 means
C.sub.1-10 alkoxy group or a C.sub.1-4 alkoxy group optionally substituted
by a phenoxy group optionally bearing a nitrogen-containing substituent,
and R.sup.1, R.sup.2 and n are as defined above; or
c) reacting a compound of general formula (I) obtained according to the
process b) above, wherein R.sup.3 stands for a methoxy or ethoxy group,
and R.sup.1, R.sup.2 and n are as defined above, with an amine of the
general formula R.sup.4 R.sup.5 NH;
to obtain compounds of the general formula (I), wherein R.sup.3 means an
R.sup.4 R.sup.5 N-- group and R.sup.1, R.sup.2, R.sup.4, R.sup.5 and n are
as defined above; or
d) reacting a compound of the general formula (I) obtained according to the
process a) above, wherein R.sup.3 means hydroxyl group, and R.sup.1,
R.sup.2 and n are as defined above, or a derivative thereof suitable for
acylating, with an amine of the general formula R.sup.4 R.sup.5 NH, to
obtain compounds of the general formula (I), wherein R.sup.3 stands for an
R.sup.4 R.sup.5 N-- group, R.sup.1 and R.sup.2 are as defined above,
except the hydroxyl groups and R.sup.4, R.sup.5 and n are as defined
above; or
e) hydrogenating a compound of the general formula (I) prepared according
to any of the processes a)-d) above, wherein one of R.sup.1 and R.sup.2 is
a benzyloxy group and the other one is as defined above or both R.sup.1
and R.sup.2 are benzyloxy groups, and R.sup.3 and n are as defined above,
to obtain compounds of the general formula (I), wherein one of R.sup.1 and
R.sup.2 is hydroxyl group and the other one is as defined above, or both
R.sup.1 and R.sup.2 represent hydroxyl groups, and R.sup.3 and n are as
defined above; or
f) hydrogenating a compound of the general formula (I), prepared according
to any of the processes c), d) or e) above, wherein R.sup.3 stands for a
4-(3-phenyl-2-propenyl)piperazinyl group and R.sup.1, R.sup.2 and n are as
defined above, to obtain compounds of the general formula (I), wherein
R.sup.3 means a 4-(3-phenylpropyl)piperazinyl group, R.sup.1 and R.sup.2
are as defined above, except benzyloxy group, and n is as defined above,
and, if desired, removing (a) protective group(s) optionally being present
in the R.sup.1 and/or R.sup.2 group(s) from the compound of general
formula (I) obtained and, if desired, converting a compound of general
formula (I) obtained to its salt and/or transforming a salt thereof to an
other salt thereof and/or, if desired, liberating the free acid or base
from a salt of a compound of the general formula (I).
According to the definition accepted in the literature ›A. L. J. Beckwith:
"Synthesis of Amides", in: "The Chemistry of Amides", Ed. J. Zabiczky,
Interscience Publishers, London (1970)! the term "a derivative suitable
for acylating" means an acid derivative being suitable for the N-acylation
of amino compounds, e.g. for the synthesis of peptides usually under mild
conditions. Acid derivatives of such type are e.g. acyl halides, first of
all acyl chlorides and bromides, acid anhydrides, mixed anhydrides, e.g.
the mixed anhydrides formed with ethyl chloroformate, as well as esters
e.g. reactive esters and the methyl or ethyl esters.
In the carrying out of the processes according to the invention the mixed
anhydride formed with ethyl chloroformate is a suitable acylating acid
derivative in the case of acids of the general formula (I); whereas the
acyl chloride is particularly useful in the case of acids of the general
formula (II).
According to a preferred embodiment of process a) of the invention, the
acyl chloride or anhydride of a compound of general formula (II) is
reacted with an amino acid of the general formula (III) or with a
derivative thereof. This reaction is carried out in water or in an organic
solvent or in a mixture thereof in the presence of an acid binding agent
at a temperature between 0.degree. C. and 80.degree. C. Suitable organic
solvents are e.g. ethers such as dioxane or tetrahydrofuran or an aromatic
hydrocarbon, e.g. benzene or toluene. An inorganic or organic base may be
used as acid binding agent. When carrying out the reaction with an amino
acid of general formula (III), it is suitable to work in a mixture of
water and dioxane in the presence of sodium hydroxide as acid binding
agent at a temperature between 20.degree. C. and 40.degree. C. When
realizing the reaction with an amino acid ester of the general formula
(III), it is suitable to work in benzene or toluene at a temperature
between 50.degree. C. and 80.degree. C. in the presence of e.g.
triethylamine as acid binding agent.
The progress and termination of the reaction can most simply be observed by
using thin layer chromatography (TLC).
According to a preferable embodiment of process b) of the invention, an
acid of the general formula (I) is reacted with an alcohol of the general
formula R.sup.3 H in an organic solvent, conveniently in an excess of the
alcohol used at a temperature between 0.degree. C. and the boiling point
of the solvent in the presence of thionyl chloride of an acid catalyst to
obtain compounds of the general formula (I), wherein R.sup.3 means a lower
alkoxy group. An inorganic of organic acid, e.g. hydrogen chloride or
p-toluenesulfonic acid may be used as acid catalyst.
Alternatively, in order to obtain compounds of the general formula (I),
wherein R.sup.3 stands for a substituted alkoxy group and R.sup.1 as well
as R.sup.2 are different from the hydroxyl group, the process b) of the
invention is preferably carried out in such a way that an acid of the
general formula (I) is reacted with an alcohol of the general formula
R.sup.3 H-in an organic solvent, suitably in a halogenated hydrocarbon
solvent, e.g. methylene chloride, in the presence of
dicyclohexylcarbodiimide and optionally a catalyst at a temperature
between 0.degree. C. and 40.degree. C. It is suitable to use a
nucleophilic catalyst, e.g. 4-(N,N-dimethylamino)pyridine.
In order to obtain compounds of the general formula (I), wherein R.sup.3
stands for an optionally substituted C.sub.1-4 alkoxy group and both
R.sup.1 and R.sup.2 are different from hydroxyl group, the process b) of
the invention is preferably performed in such a way that the acyl chloride
prepared from the acid of general formula (I) is reacted with a compound
of the general formula R.sup.3 H in an organic solvent in the presence of
an acid binding agent at a temperature between 0.degree. C. and the
boiling point of the solvent. Suitable solvents are aromatic hydrocarbons,
e.g. benzene or toluene.
According to a preferred embodiment of process c) of the invention, the
methyl or ethyl ester of an acid of the general formula (I) is reacted
with an amine of the general formula R.sup.4 R.sup.5 NH in an organic
solvent, suitably in the excess of the amine used at a temperature between
50.degree. C. and the boiling point of the solvent.
According to a preferable embodiment of process d) of the invention, an
acid of the general formula (I) is reacted with an amine of the general
formula R.sup.4 R.sup.5 NH in an organic solvent in the presence of
dicyclohexylcarbodiimide and optionally a nucleophilic catalyst at a
temperature between 20.degree. C. and 50.degree. C.
According to an other preferred embodiment of the process d) of the
invention, an acyl chloride or mixed anhydride, e.g. a mixed anhydride
formed with ethyl chloroformate prepared from an acid of the general
formula (I) is reacted with an amine of the general formula R.sup.4
R.sup.5 NH in an organic solvent optionally in the presence of an acid
binding agent at a temperature between 0.degree. C. and 80.degree. C.
In the process d) of the invention an aromatic hydrocarbon, e.g. toluene or
benzene, halogenated hydrocarbon such as methylene chloride or an
ether-type solvent, e.g. dioxane or tetrahydrofuran may preferably be used
as solvents. An inorganic or organic base, e.g. potassium carbonate or
triethylamine may be applied as acid binding agent.
According to a preferable embodiment of the process e) of the invention, a
compound of the general formula (I) is hydrogenated in a Parr apparatus in
an organic solvent in an acidic medium, suitably at a pH value between 3
and 5 in the presence of a palladium-on-carbon catalyst under atmospheric
pressure. When R.sup.3 is different from the hydroxy group, it is suitable
to use an alcohol, e.g. ethanol as solvent; when R.sup.3 stands for
hydroxyl group, an ester such as ethyl acetate, or the mixture of water
and an alcohol, or an aromatic hydrocarbon, e.g. benzene may be applied.
The pH of the reaction mixture is suitably adjusted to the value desired
by using an inorganic acid, e.g. hydrochloric acid.
Alternatively, the process e) of the invention may preferably carried out
by performing the hydrogenation under the conditions of catalytic transfer
hydrogenation. For this purpose, cyclohexene or ammonium formate are used
as hydrogen sources, whereas the catalysts and solvents defined above are
applied. This reaction is carried out at a temperature between 20.degree.
C. and the boiling point of the solvent, preferably at a temperature
between 60.degree. C. and 80.degree. C.
According to a preferred embodiment of the process f) of the invention, the
hydrogenation is carried out by using a palladium-on-carbon catalyst at
room temperature under atmospheric pressure conveniently in ethanol at a
pH value between 3 and 6.
The reaction mixture resulting from the processes described above can be
worked up by methods commonly used in the practice of organic chemistry:
e.g. by extraction, chromatography and/or crystallization following the
removal of excess of the reactant and/or solvent optionally under reduced
pressure. If desired, the compound of general formula (I) thus obtained
may be purified e.g. by using chromatography and/or recrystallization or
optionally converted to an acid addition salt which latter may be
purified, if desired, by recrystallization following its separation.
It is obvious for one skilled in the art that the compounds used in the
carrying out of process a) and b) have to be provided with protective
group(s) in order to prevent side reactions. Such protective groups are
well-known; from these, for the preparation of compounds according to the
invention benzyl group and/or acetyl group are particularly useful, which
can be removed in a known manner after carrying out the desired
reaction(s), e.g. by hydrogenolysis in the case of benzyl group and by
hydrolysis in the case of acetyl group.
Compounds of the general formula (I) according to the invention, which
contain a sufficiently strong basic group, may be transformed to acid
addition salts. This tranformation is carried out by dissolving the base
in an appropriate solvent and portionwise adding the corresponding acid or
a solution of this acid in a solvent under stirring. The product obtained
is separated by filtration or crystallization after evaporating the
solvent and, if desired, it is purified by recrystallization. An organic
or inorganic acid, preferably a pharmaceutically acceptable acid such as
hydrochloric acid, sulfuric acid, fumaric or tartaric acid may be used as
acid components. An alcohol, ester, ether and/or ketone may be used as
solvent. The salt formation is accomplished at a temperature between
0.degree. C. and 80.degree. C.: in the case of mineral acids preferably at
0.degree.-20.degree. C., in the case of organic acids preferably at
50.degree.-80.degree. C.
Compounds of the general formula (I) of the invention, wherein a free
carboxyl group is present, can form a salt with a suitable cation. Cations
of such type are suitably pharmaceutically acceptable inorganic or organic
cations such as alkaline metal cations e.g. potassium or sodium cation,
alkaline earth metal cations such as magnesium or calcium, or ammonium
cation including e.g. the cations derived from an organic
nitrogen-containing base, e.g. trialkylamine-derived cartons such as the
triethylammonium ion. These salts are prepared e.g. by dissolving the acid
in a suitable solvent and portionwise adding the corresponding base
optionally as a solution in a solvent. Alcohols, esters, ethers and/or
ketones may be used as solvents. The salt formation is carried out at a
temperature between 0.degree. C. and 80.degree. C.
Benzoic acids of the general formula (II) or the derivatives thereof
suitable for acylating in the embodiment of process a) of the invention
are for the most part known in the literature. E.g. the various isomeric
benzyloxy-hydroxy-benzoic acids and their esters are known ›see e.g.: J.
Pharm. Soc. Jap. 72, 1081 (1952); Arch. Pharm. 293, 393 (1960)!,
furthermore the various isomeric acetoxyhydroxy-benzoic acids ›see e.g.:
Arch. Pharm. 292, 282 and ibidem 341 and 731 (1959); Liebigs Ann. Chem.
1984, 1230! as well as 2-acetoxy-3-methoxy- and 2,5-di(benzyloxy)benzoic
acid and their acyl chlorides are also known ›see: J. Pharm. Chim. 18, 247
(1933) and J. Org. Chem. 29, 2078 (1964), respectively!. Compounds of the
general formula (II) not described till now can be prepared by using
processes described in the literature or by analogous methods. For these
an example will be given later in section "Preparation of Starting
Substances".
The major part of the compounds of general formula (III) used in the
process a) of the invention are known from the literature (see e.g.: T
Wieland et al.: "Methoden zur Herstellung und Umwandlung yon Aminosauren
und Derivaten", in: Houben-Weyl, Methoden der Organischen Chemie, Vol.
XI/2 page 269, Georg Thieme, Stuttgart 1958). The novel compounds can be
prepared by using methods described in the literature or analogous
processes.
The most part of the amines of general formula R.sup.4 R.sup.5 NH applied
as starting substances in the processes c) and d) of the invention are
known from the literature: e.g. the derivatives of 1,2-ethanediamine and
1,3-propanediamine as well as the 1-substituted piperazines can be
prepared as described in the literature ›see e.g.: published European
patent application No. 0.344,577; Belgian patent specification No.
523,902; published PCT patent application No. 87/01706; as well as J. Med.
Chem. 11, 804 /1968)!. The amines of general formula R.sup.4 R.sup.5 H not
yet described in the literature can be prepared by methods known from the
literature or by using analogous processes.
As mentioned above, the compounds of general formula (I) of the invention
possess valuable biological activities, e.g. lipid peroxidation-inhibiting
effect as well as a protective action against ischaemic and/or
reperfusion-induced tissue injuries and favorable central nervous system
(CNS) effects. The lipid peroxidation-inhibiting effect of the compounds
according to the invention was evaluated by the methods described
hereinafter.
A) The effect of compounds of general formula (I) on the iron)II)-dependent
peroxidation of arachidonic acid
The peroxidation of arachidonic acid was measured by using the method of J.
M. Braughler ›J. Biol. Chem, 262, 10438 (1986)! at 37.degree. C. in
methanol. The compound to be tested was investigated at various
concentrations. The peroxidation was initiated by adding 10.sup.-4 mol of
iron(II) (ferrous) ion (to result in a final volume of 0.5 ml).
The thiobarbituric acid-reactive products were determined by a modification
of J. A. Buege ›Meth. Enzymology 52, 302 (1978)! as follows. 0.55 ml of 2%
thiobarbituric acid was added to the solution and the samples were boiled
for 20 minutes. After cooling down, the samples were diluted with
distilled water, then chloroform was added. After centrifuging the tubes
at 400.times. g for 7 minutes, the quantity of the thiobarbituric
acid-reactive products was determined in the supernatant by
spectrophotometry at 535 nm. The effect of the compound to be tested was
characterized by its IC.sub.50 value (i.e. the concentration resulting in
an 50% inhibition). .alpha.-Tocopherol was used as reference compound. The
results together with those of methods B) and C) are summarized in Table
1.
B) The effect of compounds of general formula (I) on the iron(II)
ion-dependent peroxidation of brain homogenate
The measurement was carried out by using the method of J. M. Braughler ›J.
Biol. Chem. 262, 10438 (1987)!.
In these experiments OFA rats with a body-weight of 150-200 g were
decapitated and brain homogenates were prepared in Krebs buffer solution,
then the Method A) was followed.
C) The effect of compounds of general formula (I) on the NAOPH-dependent
peroxidation of brain microsomes
This study was carried out by using the method of T. J. Player and A. A.
Morton ›J. Neurochem. 37, 422 (1981)!.
1) Microsome preparation
OFA rats of 3 months age were decapitated and their whole brain was
homogenized in ice-cold 0.25M saccharose solution. After centrifuging the
homogenate at 15000.times. g for 10 minutes, the supernatant was decanted
and the residue was further centrifuged at 78000.times. g for 60 minutes.
The preparation having a concentration of 10-20 mg of protein/ml was
divided to aliquots.
2) Measurement of the microsomal lipid peroxidation
The measurement was carried out at 73.degree. C. in a reaction mixture with
the following composition; 0.05M Tris maleate (pH 6.8) buffer, 1.0 mM
KH.sub.2 SO.sub.4, 1.0 mM ADP, 0.2 nM FeCl.sub.3 and 0.4 mM NADPH. NADPH
was not added to the reaction mixture used for determination of the
baseline activity. The reaction was initiated by adding 0.5 mg of membrane
protein and stopped after incubation for 15 minutes. Subsequently, the
samples were centrifuged at 950.times. g for 20 minutes. The
thiobarbituric acid-reactive products were determined in 1 ml of
supernatant each by using the method of Z. Dunied ›Biochem. Pharmacol. 32,
2283 (1983)!.
TABLE 1
______________________________________
Lipid peroxidation-inhibiting effect of compounds of the general
formula (I)
Compound arachidonic
(Example)
acid IC.sub.50 ›.mu.mol/liter! on
No. substrate brain homogenate
brain microsome
______________________________________
24 40 4.8 37
25 15 100 100
29 100 9 4.5
31 100 16 6.6
32 100 12 7.9
34 100 46 8.6
35 27 3.3 5.3
36 3.4 100 100
37 31 100 100
.alpha.-Tocopherol
1.5 7 >100
______________________________________
It is obvious from the data of Table 1 that the lipid
peroxidation-inhibiting effect of compounds tested of the invention is
similar to or in several cases higher than of .alpha.-tocopherol used as
reference compound.
The protective action of the compounds according to the invention against
ischaemic and reperfusion-induced tissue injuries was evaluated by using
the following iv vivo methods.
A) Effect of compounds of the general formula (I) on the ischaemic
intestine injury in rats
The method of D. A. Parks et al. ›Surgery 92, 869 (1985)! was employed in
these experiments.
Male CFY rats with an average body-weight of 250 g were starved for 24
hours before the surgical intervention but water was allowed ad libitum.
The compound to be tested was orally administered in a 25 mg/kg dose by 2
hours before the operation.
The abdominal wall was opened along the median line under ether
anaesthesia. The appropriate small intestine section was made ischaemic by
ligating both small branches belonging to the pancreatico-duodenal artery.
The shame-operated control animals were subjected only to the surgical
intervention but their blood vessels were not ligated. The wound was
closed and after 2 hours the abdominal cavity of the animals was again
opened under ether anaesthesia. The thickened intestinal section was
removed, its length and weight were determined and the significance was
calculated by Duncan's test ›D. B. Duncan: Biometrics 11, 1 (1955)! (with
the weights corrected for a length of 20 mm) on the one hand, between the
sham-operated and ischaemized vehicle-control animals; and on the other
hand, between the ischaemized control animals and ischaemized animals
treated with the compound to be tested. The edema-induced weight increase
in the intestinal section was expressed as percentage. The results are
summarized in Table 2.
TABLE 2
______________________________________
Effect of compounds of the general formula (I) on the ischaemized intes-
tinal section in rats after oral administration of a 25 mg/kg dose
Compound
Inhibition of
(Example)
ischaemia
No. (%)
______________________________________
24 63
25 61
29 52
30 70
35 63
36 76
37 73
40 72
41 75
______________________________________
Based on the above results, compounds of the invention tested possess a
highly significant inhibitory effect against the adverse (harmful) sequels
of ischaemia induced in the small intestine section.
B) Investigations on the model of reperfusion-induced arrhythmia in rats
In these experiments, the reperfusion-induced arrhythmia was developed in
male SPRO rats weighing 400 g in average by using the method of D.
Lamontagne et al. ›Fundam. Clin. Pharmacol. 3, 671 (1989)!.
The chest of artificially respirated animals was opened under pentobarbital
anaesthesia and a thread was implanted under the left coronary. After an
equilibration period of 15 minutes, in the case of an arterial blood
pressure of at least 60 Hgmm, a myocardial ischaemia was induced by
ligating the coronary for 5 minutes. This was followed by a reperfusion
lasting for 10 minutes. The duration of arrhythmia, ventricular
tachycardia (VT) and ventricular fibrillation (VF), respectively,
developed within 3 minutes after reperfusion were registered in a lead-II
ECG.
The average durations of VT and VF, respectively related to 1 minute were
determined and the number of deaths induced by arrhythmia was also
registered.
The compound to be tested was orally administered one hour before the
experiment.
The statistical data were calculated by using Duncan's test (duration of VT
and VF, respectively) or the chi.sup.2 test (number of deaths) ›S. Bolton
in: "Pharmaceutical Statistics", pages 169-173 (1990), Marcel Dekkar!
following the variance analysis in relation to the vehicle control.
The results are shown in Table 3.
TABLE 3
______________________________________
Compound Dose No. of Average duration of
(Example)
(mg/kg) cases VT/VF No. of deaths
No. p.o. N S .+-. SE/min
(lethal VT/VF)
______________________________________
25 100 10 28.0 .+-. 5.1**
1/10*
50 8 37.3 .+-. 5.7
4/8
36 100 8 20.6 .+-. 6.3**
0/10*
50 8 33.0 .+-. 9.9
4/8
.alpha.-Tocopherol
250 8 27.2 .+-. 7.1**
1/8*
100 10 33.1 .+-. 7.1
4/8*
Vehicle 10 51.8 .+-. 3.1
9/10
control
______________________________________
*p < 0.05;
**p < 0.01
Based on the above results, both compounds of the invention showed a
significant protective action against the reperfusion arrhythmia in a
lower dose in comparison with .alpha.-tocopherol and considerably
decreased the lethality.
C) Study on the neurotoxicity-inhibiting effect in mice
This study was carried out by using the method of R. E. Heikkila at al.
›Science 224, 1451 (1984)! or by some modification of this method being
very suitable to investigate compounds which are potentially active
against Parkinson's disease.
The neurotoxic effect (dopamine depletion) was induced by
1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (hereinafter abbreviated:
MPTP).
Male C-57 mice weighing 30 g in average were intraperitoneally treated with
vehicle or with 100 mg/kg of the compound to be tested once daily for 3
successive days. One hour after the last administration, 40 mg/kg of MPTP
and then an additional amount of 50 mg/kg of the compound to be tested
were intraperitoneally administered. The animals were killed after 4 days,
their brain was removed and the corpus striatum was separated. The
dopamine level of corpus striatum was determined by high performance
liquid chromatography (HPLC).
The results are shown in Table 4.
TABLE 4
______________________________________
Compound
(Example) MPTP Dopamine level
% of
No. treatment (.mu.g/g tissue)
control
______________________________________
36 - 20,67 .+-. 0,5
103
+ 6,68 .+-. 1,0.sup.a
33
24 - 20,44 .+-. 0,6
102
+ .sup. 4,85 .+-. 1,7.sup.b
24
vehicle - 20,13 .+-. 0,6
100
+ 1,74 .+-. 0,2
3
______________________________________
.sup.a p < 0.01 in relation to the MPTP control
.sup.b p < 0.05 in relation to the MPTP contro1
Based on the results summarized in Table 4, the decrease in the dopamine
level developed under the effect of MPTP was significantly moderated by
the compounds of the invention.
On the basis of the pharmacological results, the compounds of general
formula (I) according to the invention are expected to be useful for the
treatment of diseases being in an indirect or direct connection with
pathological oxidation processes occurring in the organism ›B. Halliwell:
Drugs 42, 570 (1991)!. Thus, these compounds can be particularly useful
for the treatment and/or prevention of ischaemic and reperfusion tissue
injuries, inflammatory reactions, atherosclerosis, various degenerative
neurological disorders as well as for delaying the natural process of the
ageing of cells.
The toxicity of the compounds according to the invention was studied in
rats. The acute oral LD.sub.50 values of all the compounds No. 24, 25, 29,
35, 36 and 37 were found to be higher than 1000 mg/kg, i.e. low.
The effectivity and low toxicity of the compounds of the invention together
mean a valuable spectrum of activities and therapeutic safety.
For therapeutical use, the daily dose of compounds according to the
invention is usually in the range from 1 mg/kg of body-weight to 10 mg/kg
of body weight, preferably from 1 mg/kg of body weight to 5 mg/kg of body
which is optionally administered in divided daily subdoses by considering
the conditions of the adsorption.
For a therapeutical use, the active agents according to the invention are
suitably transformed to pharmaceutical compositions by mixing them with
nontoxic, inert, solid or liquid carriers and/or additives commonly used
in the pharmaceutical practice, which are useful for enteral or parenteral
administration. E.g. water, gelatine, lactose, starch, pectin, magnesium
stearate, stearic acid, talc or vegetable oils may be used as carriers. As
additives e.g. preservatives, wetting agents (surface active agents) as
well as emulsifying and dispersing agents, buffers and flavours may be
applied.
The active agents according to the invention can be transformed to the
usual pharmaceutical compositions, e.g. solid forms (such as tablets,
capsules, pills, suppositories) or liquid forms (such as aqueous or oily
solutions, suspensions, emulsions, syrups as well as injectable solutions,
suspensions and emulsion) by using the carriers and/or additives mentioned
above.
The invention also relates to the pharmaceutical compositions containing a
compound of the general formula (I) or a pharmaceutically acceptable salt
thereof as active ingredient; as well as to a process for preparing these
compositions.
The invention also relates to a method for treating diseases being in
connection with pathological oxidation processess i.e. for the treatment
and/or prevention of ischaemic and reperfusion tissue injuries,
inflammations, atherosclerosis and various degenerative neurological
disorders. This method comprises administering to the patient a
therapeutically effective amount of an active ingredient of the formula
(I) or pharmaceutically acceptable salt thereof.
The invention is illustrated in detail by the aid of the following
non-limiting Examples. The melting points given in the Examples are
uncorrected. Compounds having a melting point lower than room temperature
were characterized by the retention value (R.sub.f) obtained in thin layer
chromatography.
Abbreviations: benzyl group is abbreviated by "Bz", ethyl group by "Et" and
methyl group by "Me".
EXAMPLE 1
Preparation of 4-{N-›2,5-di(benzyloxy)benzoyl!amino-butyric acid
28.00 g (79.4 mmol) of 2,5-di(benzyloxy)benzoyl chloride were portionwise
added to a sulution containing 17.32 g (168 mmol) of 4-aminobutyric acid
in a mixture of 160 ml of water, 40 ml dioxane and 46 ml of 4M sodium
hydroxide solution at 25.degree.-28.degree. C. during 90 minutes while
stirring. After stirring the reaction mixture at 30.degree. C. for 2.5
hours, 150 ml of water were added and the pH value of the solution was
adjusted to 4 by adding 12M hydrochloric acid. The precipitate was
filtered after cooling, washed with ice-cold water and dried to give 32.9
(99%) of the aimed product, m.p.: 135.degree.-138.degree. C.
By using the appropriate acyl chloride and amino acid as described above
the compounds summarized in Table 5 were prepared.
TABLE 5
______________________________________
Compounds of the general formula (I), wherein R.sup.3 means
hydroxyl group
Example
No. R.sup.1 R.sup.2 n Yield %
M.p. .degree.C.
______________________________________
2 2-OBz 5-OBz 4 77 105-110
3 2-OBz 5-OBz 5 93 135-137
4 2-OBz 5-OBz 7 94 98-100
5 2-OBz 5-OBz 10 77 114-116
6 2-OBz 5-OBz 11 80 107-108
7 2-OBz 5-OBu 5 50 100-101
______________________________________
EXAMPLE 8
Preparation of ethyl 12-{N-›2,5-di(benzyloxy)benzoyl!amino}dodecanoate
To a solution of 4 g (7.5 mmol) of
12-{N-›2,5-di(benzyloxy)benzoyl!amino}dodecanoic acid (compound of Example
6) in 23 ml of anhydrous ethanol, 7.5 mmol of 20% ethanolic hydrogen
chloride solution were added and the reaction mixture was stirred for 4.5
hours. After cooling the precipitate was filtered, washed with ether and
dried to give 2.69 g (64%) of the aimed compound, m.p.:
70.degree.-71.degree. C.
The following compounds were prepared from the correspondig amino acid and
alkanol containing hydrogen chloride as described above:
Ethyl 11-{N-›2,5-di(benzyloxy)-benzoyl!amino}undecanoate (compound of
Example 9), yield 79%, m.p.: 50.degree.-53.degree. C.
Methyl 6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoate (compound of Example
10), yield 87%, m.p.: 61.degree.-63.degree. C.
EXAMPLE 11
Preparation of 2-›4-(acetylamino)phenoxy!ethyl 4-{N-›2,5-di(benzyloxy)
benzoyl!amino}butanoate
0.57 g (2.75 mmol) of dicyclohexylcarbodiimide was portionwise added to a
solution of 1.05 g (2.5 mmol) of
4-{N-›2,5-di(benzyloxy)benzoyl!amino}butyric acid (compound of Example 1)
in 16 ml of anhydrous methylene chloride at room temperature under
stirring. After stirring the solution at the same temperature for 10
minutes 0.54 g (2.75 mmol) of 2-›4-(acetylamino)phenoxy!ethanol and 0.03 g
(0.25 mmol) of 4-(N,N-dimethyl-amino)pyridine were added. The reaction
mixture was stirred at room temperature for 4 hours, then diluted with
methylene chloride and the solid product was filtered. The filtrate was
successively washed with 5% acetic acid, 5% sodium hydrogen carbonate
solution and water, then dried and evaporated under reduced pressure. The
residue was separated by chromatography on a silica gel column by eluating
with a 95:5 mixture of chloroform and methanol to obtain 0.82 g (55%) of
the aimed product, m.p.: 141.degree.-143.degree. C.
EXAMPLE 12
Preparation of octyl 6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoate
Step A) Preparation of 6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoyl
chloride
4.6 g (40 mmol) of thionyl chloride dissolved in 12 ml of anhydrous toluene
were dropwise added to a suspension of 9.0 g (20 mmol) of
6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoic acid (compound of Example 3)
in 60 ml of anhydrous toluene and 0.93 g (13 mmol) of anhydrous
dimethylformamide at room temperature during 5 minutes stirring. The
reaction mixture was stirred at 50.degree. C. for 1 hour then evaporated
under reduced pressure to dryness at a temperature below 50.degree. C. The
residue obtained was thoroughly triturated with ether, filtered to obtain
7.68 g (82%) of the aimed product, m.p.: 90.degree.-94.degree. C.
Step B) Reaction of the acyl chloride with 1-octanol
0.66 g (5 mmol) of 1-octanol was dropwise added to the solution of 1.5 g
(3.2 mmol) of 6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoyl chloride in 15
ml of anhydrous acetonitrile and 0.29 g (3.7 mmol) of anhydrous pyridine
during 5 minutes under cooling and stirring at 0.degree.-5.degree. C. The
reaction mixture was stirred at room temperature for 10 hours, then
evaporated under reduced pressure to dryness at a temperature below
50.degree. C. The residue obtained was dissolved in 40 ml of ether and was
successively washed with water, 2% sodium hydroxide solution and finally
with water, then dried and evaporated under reduced pressure. The residue
was purified on a silicagel column by using ethyl acetate as eluent to
give 0.96 g (54%) of the aimed compound, m.p.: 48.degree.-50.degree. C.
EXAMPLE 13
Preparation of N-(2-hydroxyethyl)-{6-{N-›2,5-di(benzyloxy)benzoyl!
amino}hexanoic acid amide}
A solution containing 1.60 g (3.5 mmol) of methyl
6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoate (compound of Example 10) in
4.9 g (70 mmol) of 2-aminoethanol was reacted under nitrogen at
100.degree. C. for 2 hours while stirring. After cooling down, the
reaction mixture was diluted with 70 ml of chloroform and acidified to pH
3 by adding 5M hydrochloric acid. After separation the aqeuous phase was
extracted twice with chloroform, the combined organic phase was washed
with water, dried and evaporated under reduced pressure. The residue was
washed with ether and recrystallized from ethyl acetate to give 1.1 g
(63%) of the aimed compound, m.p.: 103.degree.-104.degree. C.
The following compounds were similarly prepared by carrying out the
reaction with the corresponding amine at the boiling point of the amine:
N-(2-Aminoethyl)-{6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoic acid amide}
(compound of Example 14), yield 43%, m.p.: 88.degree.-89.degree. C.
N-Octyl-{6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoic acid amide}
(compound of Example 15), yield 47%, m.p.: 111.degree.-112.degree. C.
By carrying out the above reaction with a solution of methylamine in
ethanol at room temperature N-methyl-{4-{N-›2,5-di(benzyloxy)benzoyl!
amino}butanoic acid amide} (compound of Example 18), was obtained in a
yield of 88%, m.p.: 135.degree.-137.degree. C.
EXAMPLE 17
Preparation of 5-{N-›2,5-di(benzyloxy)benzoyl!amino}pentylcarbohydroxamic
acid
Step A) Preparation of 6-{N-›2,5-di(benzyloxy)benzoyl!amino} hexanoyl
chloride
0.36 g (5 mmol) of anhydrous dimethylformamide and 35 ml of anhydrous
methylene chloride were added to 2.23 g (5 mmol) of
6-{N-›2,5-di(benzyloxy)benzoyl!amino}caproic acid (compound of Example 3).
To the solution obtained 1.43 g (11.25 mmol) of oxalyl chloride were
portionwise added at 0.degree. C. under stirring, then the reaction
mixture was stirred at the same temperature for 40 minutes. The solution
thus obtained was used in the following step B).
Step B)
The solution of the acyl chloride obtained in the preceding Step A) was
added in four portions to a solution of 1.4 g (20 mmol) of hydroxylamine
hydrochloride and 3.0 g (30 mmol) of triethylamine in 17.5 ml of
tetrahydrofuran and 1.75 ml of water during 10 minutes at 0.degree. C.
under stirring. After stirring the reaction mixture at 20.degree. C. for
90 minutes, 60 ml of 2N hydrochloric acid were added, the phases were
separated and the aqueous phase was extracted twice with methylene
chloride.
The organic phase was washed with water, dried and evaporated under reduced
pressure at a temperature below 40.degree. C. The residue was purified on
a silica gel column by using a 9:1 mixture of ethyl acetate with methanol
as eluent to give the aimed compound in a yield of 16%, m.p.:
61.degree.-63.degree. C.
The compound of Example 18 was obtained by using pyrrolidone sodium salt in
dimethylformamide at 40.degree. C.
1-{6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoyl}-5(1H)-pyrrolidone
(compound of Example 18), yield 27%, m.p.: 94.degree.-95.degree. C.
EXAMPLE 19
Preparation of
1-{6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoyl}-4-methyl-piperazine
Step A) Preparation of mixed anhydride
0.24 g (2.2 mmol) of ethyl chloroformate was added to a solution of 1 g
(2.2 mmol) 6-{N-›2,5-di(benzyloxy)benzoyl!amino}hexanoic acid (compound
Example 3) in 4.5 ml of anhydrous methylene chloride and 0.22 g (2.2 mmol)
of triethylamine at 0.degree. C. under stirring. After stirring the
reaction mixture at 0.degree. C. for 30 minutes 5 ml of ice-water were
added, the phases were separated, the organic phase was dried over
anhydrous magnesium sulfate, then concentrated to a volume of 2 ml under
reduced pressure at 25.degree. C. The residual liquid was used in this
form in the next step without delay.
Step B)
The mixed anhydride prepared in the preceding step A) was poured to the
solution of 0.22 g (2.2 mmol) of methyl-piperazine in 2.2 ml of anhydrous
tetrahydrofuran at 0.degree. C., then the reaction mixture was stirred at
0.degree. C. for 1 hour. After pouring the mixture into 5 ml of ice-water,
tetrahydrofuran was distilled off under reduced pressure and the aqueous
phase was extracted with chloroform. The organic phase was washed with
water, dried and the solution was evaporated under reduced pressure. The
residue was purified by chromatography on a silicagel column by using a
10:1 mixture of chloroform and methanol as eluent to obtain 0.91 g (78%)
of the aimed compound, m.p.: 78.degree.-79.degree. C.
The compounds summarized in Table 6 were prepared as described above, i.e.
by preparing the mixed anhydride from the corresponding acid according to
step A) and by reacting the mixed anhydride with the corresponding amine
according to the step B).
TABLE 6
__________________________________________________________________________
Compounds of the general formula (I), wherein R.sup.1 means 2-benzyloxy
group, R.sup.2 stands for 5-benzyloxy group
M.p. .degree.C. or R.sub.f
Example No.
R.sup.3 n Yield %
value
__________________________________________________________________________
20
##STR5## 5 72 0,5.sup.a
21
##STR6## 5 55 139-141
__________________________________________________________________________
.sup.a chloroform/methanol = 24:1 was used as eluent
EXAMPLE 22
Preparation of 8-›N-(2,5-dihydroxybenzoyl)amino!octanoic acid
1.85 g (22.5 mmol) of cyclohexene, 0.5 g of 10% palladium-on-carbon
catalyst and 0.15 g of hydroquinone were added to a solution of 1.2 g (2.5
mmol) of 8-{N-›2,5-di(benzyloxy)benzoyl!amino}octanoic acid (compound of
Example 4) in 18 ml of anhydrous ethanol under nitrogen. After boiling
under reflux for 1 hour while stirring, the reaction mixture was cooled
down, diluted with 12 ml of water, the catalyst was filtered off under
nitrogen and washed with a 9:1 mixture of ethanol and water. After
evaporating the solvent under reduced pressure, the residue was thoroughly
triturated with 10 ml of water and then stirred at 0.degree. C. for 1
hour.
The crystalline product was filtered, washed with ice-water and dried to
give 0.35 g (46%) of the aimed compound, m.p.: 150.degree.-151.degree. C.
The compounds listed in Table 7 were prepared as described above by using
the corresponding starting substances. (In the cases of compounds of
Examples 23 and 27 a sixty-fold amount of cyclohexene was used.)
TABLE 7
__________________________________________________________________________
Compounds of the general formula (I)
Example
No. R.sup.1
R.sup.2
R.sup.3 n Yield %
M.p. .degree.C.
__________________________________________________________________________
23 2-OH
5-OH
OH 10
47 136-138
24 2-OH
5-OH
OH 11
74 142-143
25 2-OH
5-OH
OH 5
74 .sup. 126-127.sup.a
26 2-OH
5-OBu
OH 5
68 95-96
27 2-OH
5-OH
##STR7## 3
72 140-141
28 2-OH
5-OH
NHCH.sub.2CH.sub.2NH.sub.2
5
87 113-115
(dihydrochloride)
29 2-OH
5-OH
NH(CH.sub.2).sub.7CH.sub.3
5
50 101-102
30 2-OH
5-OH
##STR8## 5
61 130-131
__________________________________________________________________________
.sup.a After recrystallization from aqueous hydrochloric acid (pH = 3)
m.p.: 142-144.degree. C. (crystal dimorphism).
EXAMPLE 31
Preparation of ethyl 11-›N-(2,5-dihydroxybenzoyl)amino!undecanoate
A solution containing 3.55 g (6.5 mmol) of ethyl
11-{N-›2,5-di(benzoyloxy)benzoyl!amino}undecanoate (compound of Example 9)
in 95 ml of ethanol was adjusted to a pH value of 3 by adding concentrated
hydrochloric acid, and hydrogenated in the presence of 1.3 g of 10%
palladium-on-carbon catalyst under environmental pressure. After filtering
off the catalyst, the solution was evaporated under reduced pressure, the
residue was thoroughly triturated with 10 ml petroleum ether and dried to
obtain 1.60 g (67.3%) of the aimed compound, m.p.: 72.degree.-74.degree.
C.
The compounds listed in Table 8 were prepared as described above by using
the corresponding di(benzyloxy)benzoylamino acid derivatives as starting
substances. The compound of Example 34 was obtained from the corresponding
4-(3-phenyl-2-propenyl)piperazinyl derivative (compound of Example 20).
TABLE 8
__________________________________________________________________________
Compounds of the general formula (I), wherein R.sup.1 stands for
2-hydroxyl group,
and R.sup.2 represents an 5-hydroxyl group
M.p. .degree.C. or
Example No.
R.sup.3 n Yield %
R.sub.f value
__________________________________________________________________________
32 OEt 11
60 94-95
33
##STR9## 5
75 134-137 (dihydrochloride)
34
##STR10## 5
95 0,4.sup.a (hydrochloride dihydrate)
35
##STR11## 5
32 218-223
__________________________________________________________________________
.sup.a ethyl acetate/methanol/ammonium hydroxide = 9:1:0.5 was used as
eluent;
EXAMPLE 36
Preparation of 4-›N-(2,5-dihydroxybenzoyl)amino!butyric acid
Step A) Preparation of the acylating component
To a suspension containing 7.52 g (49 mmol) of 2,5-dihydroxybenzoic acid in
50 ml of anhydrous toluene, 0.1 mol of anhydrous pyridine was added, then
7.18 g (60 mmol) of thionyl chloride were dropped to the solution while
cooling at 10.degree. C. under stirring. Subsequently, the reaction
mixture was stirred at 60.degree. C. for 6 hours, then the solution was
decanted from the undissolved oil. The solution was evaporated at a
temperature below 30.degree. C. under reduced pressure and then evaporated
to constant weight by a pump under a pressure of 1 Torr. The yellow foam
obtained was immediately used in the next step. The product was obtained
in a yield of 6.7 g, m.p.: 55.degree.-58.degree. C.
Step B) Acylation of the amino acid
4.33 g (42 mmol) of 4-aminobutyric acid were dissolved in a mixture
containing 34 ml of water, 10 ml of dioxane and 11.5 ml (46 mmol) of 4M
sodium hydroxide solution and reacted with the acylating component
obtained in the preceding step A) as described in Example 1 to give 2.4 g
(42%) ot the aimed compound, m.p.: 152.degree.-156.degree. C.
The compounds summarized in Table 10 were prepared as described in step A)
and step B) above, respectively, from the corresponding dihydroxybenzoic
acid and amino acid as starting substances.
TABLE 9
______________________________________
Compounds of the general formula (I)
Yield M.p.
Example No.
R.sup.1 R.sup.2 R.sup.3
n % .degree.C.
______________________________________
37 2-OH 5-OH OH 4 28 144-146
38 2-OH 3-OH OH 5 50 58-64
39 3-OH 4-OH OH 3 53 159-163
______________________________________
EXAMPLE 40
Preparation of methyl 4-›N-(2,5-dihydroxybenzoyl)amino!butanoate
After dropwise adding 8.5 g (71 mmol) of thionyl chloride to 30 ml of
anhydrous methanol at 10.degree. C. during 30 minutes under cooling by ice
while stirring, the solution was stirred at the same temperature for
additional 45 minutes, then 5.1 g (20 mmol) of
4-›N-(2,5-dihydroxybenzoyl)amino!butyric acid (compound of Example 36)
were portionwise added. The reaction mixture was allowed to warm to room
temperature and stirred at 80.degree. C. for 8 hours. After filtering the
precipitate by suction and washing with methanol 3.7 g (68%) of the aimed
compound were obtained, m.p.: 155.degree.-159.degree. C.
The following compound was prepared as described above by using the
corresponding amino acid:
Methyl 6-{›N-(2,5-dihydroxybenzoyl)amino!hexanoate} (compound of Example
41), yield 73%, m.p.: 100.degree.-103.degree. C.
EXAMPLE 42
Preparation of methyl 6-›N-(2 -hydroxy-3-methoxybenzoyl)amino!hexanoate
2.3 g (10 mmol) of 2-acetoxy-3-methoxybenzoyl chloride dissolved in 18 ml
of anhydrous benzene were dropwise added to the suspension of 1.80 g (10
mmol) methyl 6-aminohexanoate hydrochloride in 2.2 g (22 mmol) of
anhydrous triethylamine and 18 ml of anhydrous benzene under nitrogen at
room temperature while stirring. After boiling under reflux for 2 hours
while stirring, the reaction mixture was cooled down, the precipitate was
filtered by suction and the filtrate was evaporated 20 ml of water were
portionwise added to the residue, the solution was extracted with ethyl
acetate, the organic phase was washed with 1M hydrochloric acid and water,
then dried. The solvent was evaporated under reduced pressure. The residue
was purified by chromatography on a silica gel column by using a 3:4
mixture of petroleum ether and ethyl acetate to obtain 1.62 g (55%) of the
title compound, m.p.: 69.degree.-70.degree. C.
Preparation of the novel starting substances is illustrated by the
following Example.
The novel benzoic acid derivatives of the general formula (II) can obtained
e.g. as follows.
Preparation of 2-benzyloxy-5-butoxybenzoic acid
A suspension containing 1.9 g (9 mmol) of 5-butoxy-2-hydroxybenzoic acid,
3.85 g (30 mmol) of benzyl chloride and 5 g (36 mmol) of anhydrous
potassium carbonate in 18 ml of anhydrous ethanol was boiled under reflux
for 20 hours while stirring. The reaction mixture was cooled to room
temperature and after adding 20 ml of water and thoroughly shaking, the
three phases formed were separated. The medium phase was boiled under
reflux with 1.1 g (27.5 mmol) of sodium hydroxide dissolved in 7 ml of
ethanol and 5 ml of water for 2.5 hours under stirring. After cooling down
the solution was mixed with 15 ml of water under cooling by ice, the pH
value of the mixture was adjusted to 4 by adding 5M hydrochloric acid and
stirred for 1 hour. After extracting the product with ethyl acetate and
drying, the solution was evaporated to dryness under reduced pressure to
give 1.5 g (55%) ot the aimed product, m.p.: 79.degree.-82.degree. C.
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